Histological slices and the like can be embedded in plastics or resins. A typical plastic or resin suitable for such embedding is "plexit 55". "Plexit" is a trademark for a methacrylate embedding resin, described by the manufacturer, Rohm GmbH, of D-6100 Darmstadt 1, Federal Republic of Germany. Plexit 55, before being polymerized, is a thickly flowable or pourable resin which can be polymerized to form a solid crystal clear body by irradiation by light from a commercial fluorescent tube.
Usually, the irradiation lamps are used in pairs, one above and one below a support element for dishes in which the histological preparations are located, embedded in the liquid resin. Upon energizing the lamps, the liquid resin will polymerize due to the presence of light from the lamps.
In histology, which is the study of biological tissues, hard and soft tissues are examined under the microscope. The term "histology" is also understood to include an analytical technique with which morphological and histochemical tests can be performed on organic and inorganic hard and soft tissue samples. Since the tests must be performed under the microscope using thin slices approximately 1 micrometer thick, the tissue samples are first embedded in an embedding material, and a thin section or slice of the embedded preparation can then be prepared. As an alternative to a preparation embedded in a medium, slices of deep-frozen soft tissue specimens are also prepared.
In addition to the technique of embedding tissue specimens in plastic or resin, another technique currently used is to embed the specimens in paraffin.
One problem in embedding tissue preparations, especially soft tissue preparations, is how to harden or cure the embedding material with little heat buildup or bubble formation, so that soft tissues, in particular, will be prevented from undergoing any change.
The referenced articles in the literature describe the embedding of bone preparations, and apparatus therefor.
In the known irradiation cabinet, the embedded tissue preparations that are to be cured and that have for instance been put into a glass dish are placed on a glass work counter. Two sets of five fluorescent tubes (20 to 60 W in power) are connected in pairs, one set being located above and the other below the glass counter. The glass counter and the array of fluorescent tubes are mounted in a vertically adjustable manner, so that the spacing between the embedded preparation and the upper and lower fluorescent tubes can be varied. The pane of glass on which the chambers having the specimens to be embedded are placed has a thickness of approximately 10 to 15 mm. The irradiation cabinet is open at the back so that the reaction heat and vapors given off during the curing can dissipate. The up to five groups of lamps can be turned on and off as needed by switches. Since curing these plastics entails a considerable heat buildup, the light is switched off from time to time until the embedding material has cooled down. For monitoring the thermal development, a contact thermometer may be provided in the embedding material.